The union's Illinois council and Mr. Quinn, a Democrat, have brawled mightily over a variety of fiscal issues, most notably pension reform. But with GOP nominee Mr. Rauner viewed as a vehement enemy of public-sector unions, those differences have been patched over.

The $500,000 is going to one of those nice "independent" expenditure groups, Illinois Freedom PAC, that can't legally coordinate with the Quinn campaign but has been bashing Mr. Rauner with vigor.

The group says it's not going to say what it will do with the $500,000. But it's a good bet it will go into the gubernatorial race, quite possibly behind the TV spot the group is airing now that talks about how Mr. Rauner's former private-equity firm, GTCR LLC, outsourced jobs oversees and quotes the candidate himself as saying that "not every job should be in America."

You wouldn't want to be able to watch a little tube without some political dirt, now, would ya?